Surgical devices such as staples made from stainless steel are becoming more frequently used in the medical profession as substitutes for and/or complements to surgical sutures and ligatures. In some surgical procedures, the staples are used internally. For instance, in a bowel resection, single or multiple rows of staples are deployed circumferentially around each bowel end that is to be rejoined. Staples thus employed are not removed, but are left inside the patient. While the body has ways of isolating such foreign objects that are left inside a patient so that the staples are not detrimental, surgeons would prefer to use absorbable staples that would eventually disappear from the body after their function during wound healing has been served.
It has been proposed to produce staples from synthetic absorbable polymers. For instance,, many patents that relate to synthetic absorbable polymers disclose surgical staples as one of many proposed uses. However, thus far, surgical staples made from synthetic absorbable polymers have not yet been used in the medical profession because the polymers have yet to achieve the requisite combination of properties. A staple made from an absorbable polymer must have sufficient stiffness to penetrate tissue, it must retain sufficient strength to perform its function during the wound healing process, and then eventually be absorbed by the body. It has proven to be especially difficult to achieve this necessary combination of properties.
Unlike the case with staples, surgical ligating clips made from synthetic absorbable polymers are being used in the medical profession. Such clips ordinarily comprise two legs joined by a hinge, with locking means at the ends of the legs that are opposite the hinge ends. The beam stiffness of the two legs is important for maintaining tight closure of the clip. By increasing the stiffness of the polymer from which the clip is made, either the beam stiffness can be increased or the size of the legs can be reduced.
This invention provides a means for improving the stiffness and other key mechanical properties of synthetic absorbable polymers, and therefore enhances the utility of staples, ligating clips, and other surgical devices made from such polymers.